1. Field of the Invention
The present invention relates to pipe joining tools and more specifically to a tool for joining plastic pipe sections to fittings such as a coupling, elbow, tee, 90 or other fitting.
2. Description of the Prior Art
Polyvinyl (PVC) pipe sections are joined one to another by PVC pipe fittings. To join a pipe section to a pipe fitting, a free end of the pipe section is cut square, burrs are removed, the pipe is cleaned, a primer is applied, and PVC plastic pipe cement is applied to the free end of the pipe section and to the inside surface of one socket of the fitting. The fitting and a free end of the pipe section are pulled together to force the pipe section into a socket of the fitting. In order to avoid trapping air in the cement, which results in a weak joint, the fitting should be rotated one quarter turn as the free end of the pipe section enters the fitting socket. Once the free end of a pipe section is inserted into the fitting socket, the joint so formed must remain under compressive force for a period of time to permit the cement to begin to set, generally ranging from thirty seconds to several minutes depending on ambient temperature, diameter of the pipe, and other factors. The procedure can then be repeated using an opposite socket of the same fitting and a free end of another pipe section, thereby joining two pipe sections. If one attempts to perform this procedure by grasping the pipe section in one hand and the fitting in the other hand, and then pushing and holding the fitting and pipe section together, one encounters at least two problems (particularly with larger diameter PVC and CPVC pipe sections, i.e., 6 inches or more): it is difficult to avoid bounce between a pipe section and the fitting into which it is being inserted, and a high degree of sustained compressive force is required to hold the fitting and pipe section together while the cement begins to set.
Manually operable tools have been previously described for pulling and holding together a pipe section and a pipe fitting by compressive force. Illustrative of such tools are the pipe mating tool of Topper, U.S. Pat. No. 4,015,323 (Apr. 5, 1977), the plastic pipe assembly tool of Bjalme, et al., U.S. Pat. No. 3,831,256 (Aug. 27, 1974), and the pipe coupling device of Carter et al, U.S. Pat. No. 3,668,766 (Jun. 13, 1972). Although such tools of the prior art can provide adequate force to hold a free end of a pipe section immobile inside a fitting socket and without bounce, they provide no means for rotating the fitting a quarter turn during the procedure. Moreover, the designers of such tools have generally failed to recognize and provide for the fact that plastic pipe sections are often joined under field conditions, e.g., emplacement in a trench, where mud and debris may be expected to clog moving parts such as hinges, sprockets and gear trains. My invention is directed to a special purpose tool that efficiently performs its intended purpose and without the aforementioned drawbacks.